1. Field of the Invention
The present invention relates to an optical deflector to defect light.
2. Description of the Related Art
Japanese Unexamined Patent Application Publication No. 2005-517990 discloses a micro-machined optical deflector. This optical deflector includes a movable portion having a mirror plane, which is rotatably supported by combined torsion bars. Each combined torsion bar includes a plurality of torsion bars arranged in an array form to be parallel to a rotation axis, one end of each torsion bar being connected with one end of another adjacent torsion bar.
In the optical deflector mentioned above, when a load in a mirror plane perpendicular direction, i.e., a direction perpendicular to the mirror plane, is applied to the movable portion due to vibration or the like from its external environment, the movable portion is easy to move in the mirror plane perpendicular direction. To suppress movement of the movable portion in the mirror plane perpendicular direction, an aspect ratio of the torsion bar is adjusted. Specifically, an aspect ratio of the torsion bar relative to a width thereof is set to 1 or more. That is, a thickness dimension of the torsion bar is set to be larger than a width direction of the same, and rigidity of the torsion bar in the mirror plane perpendicular direction is increased, thereby suppressing movement of the movable portion in the mirror plane perpendicular direction. However, this solution method increases the rigidity of the combined torsion bar in the mirror plane perpendicular direction and also increases the rigidity of the combined torsion bar in a movable portion rotating direction. This decreases rotational sensitivity, i.e., drive sensitivity of the movable portion relative to drive force.
In view of the above-described actual situation, an object of the present invention is to provide an optical deflector having improved resistance of a movable portion relative to a load in a mirror plane perpendicular direction.